In cultivating fresh water and salt water fish it is generally necessary to provide artificial food sources to supplement whatever natural food sources may be present. A variety of foods are fed to cultivated fish in both natural and controlled environments, e.g., in aquariums or special tanks or ponds.
For example, naturally occurring water animals such as Daphnia pulex, Artemia salinas (brine shrimp), mosquito larvae, Tubifex worms, and Cyclops have been used as fish foods. Natural foods are often best for optimum fish growth and condition. However, these natural foods are laborious and costly to produce and are usually restricted by inconsistent availability and erratic quality, may have a short lifetime, and are difficult to keep. In addition, the availability of such natural foods is largely seasonal.
For these reasons, many types of processed or prepared fish foods have been introduced commercially. These commercial fish foods include baked and ground cake type foods, flaked foods, and frozen or air dried foods. Such commercial fish foods suffer from a number of disadvantages. Processed or prepared foods are less expensive but may not provide for optimal growth and may not bring fish to a breeding condition. Moreover, the coloration of cultivated fish fed such processed or prepared foods may be drab. This is especially a problem in the case of fish that are prized for their attractive coloration, such as koi.
Insects have been used in the past to feed fish. Silkworm pupae have been used as a component of the diet of carp in Japan and China (Hickling, Fish Culture, Faber and Faber: London, 1962). Light traps have been used to attract aerial insects to supplement the diet of bluegill (Heidinger, Prog. Fish-Cult., 33:187-192, 1971). Pupae of face fly (Musca autumnalis) have been fed to channel catfish (Loyacano Jr., Proc. Annu. Conf. Southeast Assoc. Game Fish Comm., 28:228-231, 1974). Channel catfish and tilapia fed chopped soldier fly larvae or chopped larvae as a supplement replacing 25, 50, or 75% of commercial fish feeds during a ten-week test displayed no difference in fish weight gain or length as a result of the diets fed (Bondari and Sheppard, Aquaculture 24:103, 1981).
A need exists for a fish food that is acceptable and nutritional, particularly one which supports good growth and coloration at an acceptable feeding efficiency.